Auto-immunity in children with diabetes mellitus and in their relatives

Prevalence of Organ-Specific Autoimmunity in Patients With Type 1 Diabetes Mellitus

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is associated with other autoimmune disorders that are characterized by presence of organ-specific autoantibodies. The present study was undertaken to assess the prevalence of organ-specific autoantibodies among newly diagnosed T1DM subjects of India and to study its relationship with glutamic acid decarboxylase antibody (GADA). We also compared the clinical and biochemical parameters in GADA-positive and -negative T1DM subjects.

METHODS

In a hospital-based cross-sectional study, we studied 61 patients with newly diagnosed T1DM ≤ 30 years of age. T1DM was diagnosed on the basis of acute onset of osmotic symptoms with or without ketoacidosis, severe hyperglycaemia [blood glucose > 13.9 mmol/l (>250 mg/dl)] and insulin requirement from the onset of diabetes. Subjects were screened for autoimmune thyroid disease (thyroid peroxidase antibody [TPOAb]), celiac disease (tissue transglutaminase antibody [tTGAb]), and gastric autoimmunity (parietal cell antibody [PCA]).

RESULTS

Of the 61 subjects, more than one-third (38%) had at least one positive organ-specific autoantibody. In particular, 13 (21.3%) were found to be positive for TPOAb, nine (14.8%) were positive for tTGAb and 11 (18%) were positive for PCA. GADA was positive in 15 (25%) subjects. The frequency of TPOAb tended to be higher in patients who had GADA positivity compared with those with no circulating GADA (40% vs. 15.2%; p=0.07). Subjects positive for GADA were also more likely to be PCA positive compared with those who were GADA negative (40 vs.10.9%, p=0.02). There were no differences in frequency of diabetic ketoacidosis, body mass index, hemoglobin A1C (HbA1c), insulin requirement or fasting C-peptide in GADA-positive and -negative patients.

CONCLUSION

We support the recommendation for regular screening of organ-specific autoantibodies, in particular TPOAb, tTGAb and PCA in all patients with T1DM. Detection of these autoantibodies at onset may prevent complications associated with delayed diagnosis of these disorders. We also conclude that there is higher frequency of TPOAb and PCA in GADA-positive T1DM patients as compared to negative ones. However, patients with positive GADA had similar clinical and biochemical parameters compared to GADA-negative subjects. Lastly, low GADA positivity in our study cohort as compared to Western populations suggests the heterogenous nature of T1DM in the Indian population.

Type 1 Diabetic Populations Have an Increased Prevalence of Parietal Cell Antibody: A Systematic Review and Meta-Analysis

The presence of parietal cell antibody (PCA) in serum is a biomarker of autoimmune gastritis. PCA directly recognizes the H/K ATPase expressed in parietal cells, which is responsible for the active transport of hydrogen ions in exchange for potassium ions to increase the acidity of gastric secretions. Type 1 diabetes mellitus (T1DM) mainly results from pancreatic β-cell destruction due to cell-type specific autoimmunity. Considering autoimmune factors may be the common characteristics of both PCA positivity and T1DM, it is likely that both disorders may coexist within the same patient. The main objective of this meta-analysis is to provide a reliable evaluation to clarify the association between PCA positivity and T1DM by combining the raw data from all of the relevant studies.Literature databases, including the Medline, Embase, and Web of Science, were systematically queried for studies investigating the association between PCA positivity and T1DM and were published from January 1980 to December 2014. A total of 3,584 T1DM cases and 2,650 non-T1DM controls were included in this meta-analysis, which showed that PCA positivity was more prevalent in patients with T1DM than healthy controls. Publication bias testing found no significant biases and sensitivity analysis demonstrated that our statistics were relatively stable and credible.Our findings suggested that T1DM was associated with an increased risk of PCA positivity compared to control populations.

Prevalência de auto-imunidade tireoidiana em um grupo de pacientes com diabetes mellitus tipo 1 em Londrina, PR

A auto-imunidade tireoidiana é uma co-morbidade freqüente entre pacientes com diabetes mellitus tipo 1 (DM1). Neste estudo, avaliamos a prevalência da positividade para auto-anticorpos anti-tireoidianos (anti-microssomal, anti-Tg e anti-TPO), bem como características clínicas (idade, sexo, duração do DM) e laboratoriais (função tireoidiana, HbA1) de 101 pacientes (idade média de 20 ± 9,6 anos; 62 do sexo feminino) com DM atendidos no HC/UEL. RESULTADOS: A presença de auto-anticorpos foi detectada em 31 pacientes (30,7%). No grupo com idade <12 anos, a prevalência de anticorpos foi de 15%; entre 12-18 anos, 32%, e >18 anos, 35,7% (p= 0,22). Entre os 31 pacientes com anticorpos positivos, 40% apresentava alguma disfunção tireoidiana, comparados a apenas 4,4% daqueles sem anticorpos (p<0,001). O TSH médio foi maior no grupo com anticorpos presentes (3,75 vs. 2,32µU/mL; p= 0,01). CONCLUSÃO: A prevalência da positividade para anticorpos marcadores de tireoidite auto-imune foi de em 30,7%, compatível com a literatura.

Prevalence of 20S proteasome, anti-nuclear and thyroid antibodies in young patients at onset of type 1 diabetes mellitus and the risk of autoimmune thyroiditis

Patients with type 1 diabetes mellitus (DM1) are at high risk to develop further autoimmune disorders, which are mostly characterized by the presence of organ-specific antibodies in serum and a subclinical disease course. Diabetes-related (glutamic acid decarboxylase, tyrosine phosphatase, IA-2) and thyroid-specific (thyroperoxidase, thyroglobulin) as well as antibodies to 20S proteasome, and anti-nuclear antibodies, were measured at DM1 onset in 147 children and adolescents. Patients were followed prospectively for the development of autoimmune thyroiditis (TSH elevation and/or sonographic thyroid gland enlargement in the presence of thyroid antibodies) up to 12 years, median observation time 4.4 years. Eight of 147 (5.4%) patients developed autoimmune thyroiditis. The cumulative incidence (+/-SE) at 5 years was 0.08+/-0.03. The prevalence of thyroid antibodies was 16.7%, of DM-related 88.4%, 20S proteasome 21.9%, and anti-nuclear antibodies 20.0%. There was a positive correlation between thyroid and anti-nuclear antibodies (p <0.001). Clinical course of DM1 and remission duration were not influenced by the presence of autoantibodies. However, in contrast to patients without antibodies, those with positive antibodies had significantly (p <0.001) elevated cumulative incidence of autoimmune thyroiditis at 5 years: thyroperoxidase 0.40+/-0.13, thyroglobulin 0.38+/-0.15, and anti-nuclear antibodies 0.29+/-0.12, respectively. These data underline that autoimmunity in patients with DM1 is not only restricted to beta-cell antigens at the onset of disease. In particular, patients with positive thyroid and anti-nuclear antibodies are at high risk to develop autoimmune thyroiditis during the first 5 years of DM1.

Long term persistence of anti-HBs protective levels in young patients with type 1 diabetes after recombinant hepatitis B vaccine

The aim of the present study was to evaluate the persistence of anti-hepatitis B protective levels in young patients with type 1 diabetes, successfully immunised with a recombinant hepatitis B vaccine. We re-evaluated, after a 4 year follow-up, 54 patients and 70 age and sex-matched healthy subjects. Protective antibodies levels were found in 50/54 (92%) patients and in 67/70 (96%) controls. Moreover, anti-HBs levels were similar in diabetic patients and controls (means of log-titre and (sd); 1.95 (0.88) and 2.18 (0.64) patients and controls, respectively; P=0.11). No cases of clinical hepatitis were reported and all patients and controls remained HBc negative. These data demonstrate the persistence of anti-HBs levels in children, adolescents and young patients with type 1 diabetes after recombinant hepatitis B vaccine showing evidence of longterm immunogenity and protective effect.

Anticardiolipin antibodies in first-degree relatives of type 1, insulin-dependent, diabetic patients

First-degree relatives (FDRs) of diabetic patients are at risk of IDDM, and frequently present several autoantibodies. We detected anticardiolipin antibodies (aCL) in 42 FDRs, aged 12.4 +/- 4.2 years and in 52 controls. aCL (IgG and IgM) were measured by ELISA and their results expressed in arbitrary units. All FDRs underwent islet cell antibodies (ICA) measurement, intravenous glucose tolerance test and HbA1c levels. HLA typing and HLA-DQ molecular analysis were performed in all FDRs. Positive levels of aCL-IgG were observed in 8/42 FDRs and no control subject (p = 0.04); aCL-IgM values were similar in FDRs and controls. No correlation was found between aCL levels and chronologic age or HbA1c levels. No association was observed between aCL frequency and immunologic (ICA), metabolic or genetic (HLA) parameters. No FDR showed any feature of antiphospholipid syndrome. aCL-IgG presence in FDRs is suggestive of a need to carry out a follow-up study to establish the significance of these antibodies.

Celiac disease and type I (insulin-dependent) diabetes mellitus in childhood: follow-up study

To ascertain the specificity of IgA and IgG antigliadin (IgA-AGA, IgG-AGA), IgA-antireticulin (R1-ARA), and antiendomysial (AEA) antibodies for the diagnosis of celiac disease, we evaluated 133 type I diabetic children aged 1.4-28.4 years (mean 14.1 +/- 6.6), with diabetes from onset to 20.5 years. Fifty-three patients were considered at onset and 49 of these also during follow-up. IgA-AGA and IgG-AGA were determined by enzyme-linked immunosorbent assay (ELISA), R1-ARA and AEA by indirect immunofluorescence. IgA-AGA were positive in 20 of 133 (15%), IgG-AGA were positive in seven of 133 (5.26%), while R1-ARA and AEA were positive in three patients. At the onset of disease we found elevated IgA-AGA in 17 of 53 (32%) patients, IgG-AGA in four (7.55%) patients, three of them with IgA-AGA as well; R1-ARA and AEA were present in three (5.66%) patients, all with high IgA-AGA levels. During 1-10 year follow-up IgA-AGA decreased to within the normal range in 13 patients, with elevated IgA-AGA at onset but without R1-ARA and AEA; in four patients with high IgA-AGA at onset, IgA-AGA remained constantly elevated as did R1-ARA and AEA in three of them; and two patients, without IgA-AGA, R1-ARA, and AEA at onset, became positive for all three antibodies. Intestinal biopsy confirmed a diagnosis of celiac disease in five of these with IgA-AGA, R1-ARA, and AEA, but not in one patient with persistent IgA-AGA but no AEA and R1-ARA, suggesting that R1-ARA and AEA are more reliable markers for the screening of celiac disease in type I diabetic patients.

IDDM and autoimmune thyroid disease in the pediatric age group

Diabetic patients have increased chances of developing autoimmune thyroid disease. Thyroid autoantibodies (Th-AAb) are more frequent in IDDM children than in the general population, ranging between 7 and 40%. As markers of thyroid autoimmunity, we assessed Th-AAb (MsA and TgA) cross-sectionally in 212 children and adolescents (93 girls and 119 boys) aged 1.2-21 years with IDDM from 0-18 years, and longitudinally in 90/212 (43 girls and 47 boys) at diagnosis and during a 3-10 year follow-up. In the cross-sectional study Th-AAb were found in 22/93 girls (23.7%) and 13/119 boys (10.9%). In the longitudinal study Th-AAb were observed at diagnosis in 6 patients, and during the follow-up in 9 girls. In 11/15 Th-AAb positive patients anti-nuclear antibodies were also present. Hormonal assessment revealed hypothyroidism in 3 girls (afterwards on replacement therapy), thyroid ultrasonography showed abnormal patterns in 5 girls, fine needle aspiration biopsy confirmed Hashimoto's thyroiditis in 9 (8 girls and 1 boy), with a higher frequency than that reported among healthy subjects (1-2%). Thyrotoxicosis also occurs with increased frequency in diabetic children than in the general population. We observed Graves' disease in only 1/212 IDDM patients, a 13 year-old boy in whom thyrotoxicosis developed 4 years after diabetes was diagnosed. The high prevalence of thyroid autoimmunity in our patients, particularly in females, suggests that diabetic children and adolescents should be screened for thyroid autoimmunity even if asymptomatic for hypo- or hyperthyroidism. Patients with IDDM and autoimmune thyroid disease should be evaluated for autoantibodies against other organs, such as adrenal glands and gastric mucosa. It is known that patients affected by type 1 (insulin-dependent) diabetes mellitus (IDDM) may have autoantibodies against different organs, such as thyroid, adrenal glands, gastric mucosa, parathyroid, with or without evident dysfunction of the target organ /1-8/. Among organ-specific disorders, autoimmune thyroid disease (ATD) is frequently associated with IDDM and the presence of thyroid autoantibodies (Th-AAb) has been considered a risk factor for the development of hypo- or hyperthyroidism /9/.

Organ- and non-organ-specific auto-antibodies in children with hypopituitarism on growth hormone therapy

Serum non-organ-specific antibodies (NOSA) against nuclear, mitochondrial (AMA), smooth muscle, liver/kidney microsomal (LKM), reticulin, ribosomal, and organ-specific antibodies (OSA) against pituitary gland, gonads (testis, ovary) adrenal cortex, thyroid (thyroglobulin and microsomal), pancreas islet cells, gastric parietal cells and intestinal epithelial cells were evaluated in 45 patients with hypopituitarism (mean age 12.4 +/- 4.0 years). In 22 of them, 9 with isolated growth hormone (GH) deficiency (IGHD) and 13 with multiple pituitary hormone deficiency, MRI showed anterior pituitary hypoplasia with structural stalk abnormality and ectopic posterior pituitary. Twelve had isolated small anterior pituitary and IGHD and 11 had normal morphology of pituitary gland and IGHD. Controls were healthy age-sex-matched subjects. Thyroid antibodies were detected by a passive haemagglutination test while indirect immunofluorescence was used for the others. The auto-antibodies were found in 7/45 asymptomatic patients, a frequency not significantly different from that in controls; 5 were type NOSA and 2 type OSA. Pituitary antibodies were positive in 1 girl with IGHD and normal pituitary morphology. One girl developed hyperthyroidism during the follow up. Autoantibodies were equally distributed between the three groups and the frequency was not dissimilar from that in controls; this suggests that these patients are not at a higher risk of developing auto-immune disease, at least during the first two decades.

CONCLUSION

Pituitary insufficiency in children with different MRI features seems unlikely to be secondary to an auto-immune process.

Anticardiolipin antibodies in children and adolescents with insulin-dependent diabetes mellitus

Anticardiolipin antibodies were determined in 29 diabetic children and adolescents, aged 3.9-26.8 years, with disease duration from 1 month to 19 years. Anti-islet cell antibodies (ICA-IgG and CF-ICA), anti-insulin antibodies (IAA), antithyroid antibodies and non organ-specific (NOSA) antibodies were also determined. Patients were grouped according to insulin-dependent diabetes mellitus (IDDM) duration: group I (n = 11) < 6 months, and group II (n = 18) > 5 years. Eleven of group II patients showed precocious signs of micro-angiopathic complications. Forty-two age- and sex-matched healthy subjects served as controls. IgG and IgM anticardiolipin antibodies were evaluated by ELISA and their results expressed as arbitrary units (AU). IgG anticardiolipin antibodies were found in 7 patients (24%), while IgM anticardiolipin antibodies were absent in all. IgG anticardiolipin antibodies were more frequent in IDDM patients than in controls (P < 0.005) and group I (in 6 out of 11 patients; 54.5%) than in group II (in 1 out of 18 patients; 5.5%) (P < 0.025). In five out of six group I patients with IgG anticardiolipin antibodies, ICA-IgG and/or CF-ICA were also found. No correlation was observed between anticardiolipin and other auto-antibodies, micro-angiopathic complications, and HLA typing.

CONCLUSION

Anticardiolipin antibodies may reflect an abnormal immunological response in the early stage of diabetes mellitus and represent a transient auto-immune phenomenon.

A study of thyroid function and prevalence of thyroid autoantibodies in an African diabetic population

It is generally believed that autoimmune disorders are uncommon in Africans. Some workers have argued that insulin-dependent diabetes mellitus (IDDM) is rare in Africa on account of this reduced proneness to autoimmunity. However, it is undetermined whether or not Africans with IDDM have increased prevalence of thyroid dysfunction and autoimmunity, two phenomena strongly associated with Caucasian IDDM. We determined thyroid function and the prevalence of thyroid autoimmunity in IDDM Africans. The results are compared with those of a nondiabetic group and a group with non-insulin-dependent diabetes mellitus (NIDDM). Thyroid hormone levels were significantly lower in IDDM patients than in the control population and the NIDDM population. Subclinical hypothyroidism was present in 21% of the 28 IDDM patients. One patient was hypothyroid and another hyperthyroid. Of the 60 NIDDM patients, 5 (8.3%) had subclinical hypothyroidism. Forty-six percent of the IDDM patients had significant levels of serum thyroid autoantibodies (TAAB). This was significantly higher than the 1.4% and 1.7%, respectively, in the controls and NIDDMs. Presence of TAAB in the patients was strongly associated with thyroid dysfunction, female preponderance, and duration of diabetes mellitus. Thyroid dysfunction and autoimmunity are common in Nigerians clinically diagnosed as IDDM, and have prevalence rates comparable to other populations but higher than rates previously reported from some other African groups. The increased prevalence of thyroid autoimmunity in the IDDM supports the view that these patients are true IDDMs rather than variants of NIDDM or malnutrition-related diabetes mellitus (MRDM) as has been suggested by some workers.

Final height attainment in girls and boys with insulin-dependent diabetes mellitus

We compared final height to height at diagnosis (expressed as a standard deviation score, SDS), predicted adult height (according to the Bayley and Pinneau method) and target genetic height (expressed as mean parental height in cm, +6.5 for males and -6.5 for females) in 37 patients (15 males, 22 females) with insulin-dependent diabetes mellitus (IDDM), aged 20.6 +/- 3.3 years (16.6-27), with 11.8 +/- 3.7 years (5.2-19.2) mean duration of disease. In the 22 females, final height (162.4 +/- 5.7 cm; range, 150-174 cm) was higher than predicted (161.5 +/- 7.8 cm; range, 146-176.2 cm) and target genetic height (159.7 +/- 3.8 cm; range, 152.8-167.3 cm), although not significantly. Female patients showed a positive correlation between final height and both predicted (P < 0.05) and target genetic height (P < 0.005). No difference was observed in final height between patients diagnosed in the prepubertal or pubertal phase (162.2 +/- 4.6 cm vs. 163.4 +/- 6.2 cm; P-value n.s.). In the 15 males, final height (173.4 +/- 4.4 cm; range, 166.5-181 cm), lower than predicted (175.4 +/- 4.9 cm; range, 166-183 cm), was higher than target genetic height (169.9 +/- 4.8 cm; range, 162.4-177 cm) (P < 0.05). Male patients showed a positive correlation between final height and target genetic height (P < 0.05). No difference was found in final height between patients diagnosed in the prepubertal or pubertal phase (173.6 +/- 3.5 cm vs. 172.7 +/- 5.5 cm; P-value n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytotoxic activity in children with insulin-dependent diabetes mellitus

We determined the percentage of circulating natural killer (NK) cells, using the monoclonal antibodies anti-CD57 and anti-CD16, NK cytotoxic activity (lytic units/10(6)) and lymphokine-activated killer (LAK) activity in 25 IDDM patients aged 3-23 years, 12 with disease for < 1 year (Group I) and 13 with disease for > 3 years (Group II). Nine age-matched healthy subjects served as controls. The percentage of CD57+ cells was similar in IDDM patients and controls, while the percentage of CD16+ cells was lower in IDDM patients (P < 0.05) than in controls. NK cell cytotoxic activity was lower in IDDM patients than in controls (P < 0.01), in Group I and II compared with controls (P < 0.005). LAK activity was similar in IDDM patients and in controls. No correlation was found between NK cytotoxic activity and metabolic control, HLA typing, while a negative correlation was found between NK cytotoxic activity and insulin requirement (P < 0.05). The decreased NK cytotoxic activity observed in our patients, in particular in long-standing diabetics, with normal NK cell number, could be due to a qualitative defect of the NK cells, or to a deficient IL-2 and/or TNF-alpha production, or to a immunomodulatory or immunosuppressing effect of insulin.

Thyroglobulin antibodies in type 1 diabetic patients and their relatives--measurement with highly sensitive assay

Autoimmunity in Type 1 (insulin-dependent) diabetes mellitus was assessed by measuring thyroglobulin antibodies (TGA) using a highly sensitive enzyme immunoassay in 65 young patients with Type 1 diabetes mellitus, 83 healthy first-degree relatives of the patients, 37 healthy control subjects and 67 healthy parents of the control subjects. TGA were found in 78.5% (51/65) of patients and were significantly more frequent in patients than in control subjects (40.5%, 15/37; P < 0.01). The prevalence of TGA in patients showed no correlation with age at onset, duration of diabetes or sex. Among the first-degree relatives the prevalence of TGA was significantly increased in mothers of patients than in mothers of the control subjects (80.0% vs. 54.3%, P < 0.05), while not significantly between fathers of patients and fathers of control subjects or between siblings of patients and control subjects. Comparing the TGA levels of TGA-positive subjects, the TGA levels in patients, their parents and their siblings were significantly higher than those in the corresponding control subjects (P < 0.05, P < 0.05 and P < 0.01, respectively). In the present study we thus more clearly demonstrated autoimmune diathesis in patients with Type 1 diabetes and in their first-degree relatives.

CD5-positive B cells in type 1 (insulin-dependent) diabetic children

We have measured CD5+ B cell levels in the peripheral blood of 35 type 1 (insulin-dependent) diabetic children, aged 1.1-21.2 years (10.7 +/- 4.6 years). Patients were divided into two groups according to disease duration (group I < 6 months and group II > 1.5 years). Group I included 18 patients and group II 17 patients. Thirty-nine healthy subjects, comparable for age and sex, served as controls. CD5+ B cells were identified by double immunofluorescence staining with rhodamine-conjugated rabbit anti-human immunoglobulin and with a mouse anti-CD5 monoclonal antibody revealed by a fluorescein-conjugated goat anti-mouse immunoglobulin. We found that CD5+ B cell levels (expressed as percentages of peripheral blood B lymphocytes) were significantly higher in group I (median 24; range 4-48) than in controls (median 14; range 0-36, P < 0.001) and in group II (median 4; range 0-20, P < 0.001). A follow-up study of 12 group I patients showed a significant decline in CD5+ B cell levels. The data obtained in our diabetic patients suggest that CD5+ B cells are expanded in the early phase of type 1 diabetes mellitus and may play a role in the autoimmune process of the disease.

HLA and immunoglobulin polymorphisms in idiopathic dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is an idiopathic heart muscle disorder. The presence of circulating cardiac antibodies and the association with HLA-DR4 are consistent with autoimmune pathogenesis in a subset of patients. Sixty-eight DCM patients and 277 controls were typed for IgG heavy-chain constant region (Gm) and kappa light-chain (Km) allotypes. All patients and 210 of the 277 controls were HLA-DR typed. The Gm (1, 3, 17; 23; 5*, 21, 28) phenotype was overrepresented in DCM compared with controls (25% vs 13%, p = 0.0139, pc = NS, RR = 2.23). The frequency of this phenotype was higher in patients with younger age at onset, shorter symptom duration, and among those who were positive for cardiac as well as for non-organ-specific autoantibodies than in controls. A higher frequency of the Gm (1, +/- 2, 3, 17; +/- 23; 5*, 21, 28) heterozygous phenotypes was also found in DCM compared to controls (40.91% vs 26.89%; p = 0.02, pc = 0.04, RR = 1.88). The finding of Gm heterozygosity in DCM was associated with serum positivity for cardiac antibodies. A higher proportion of DCM patients were positive for both the Gm (1, 3, 17; 23; 5*, 21, 28) phenotype and HLA-DR4 compared to normals (3/68 vs 0/210; p = 0.04, RR = 22.50).(ABSTRACT TRUNCATED AT 250 WORDS)

Antireticulin antibodies in sera of children with insulin-dependent diabetes mellitus

Sera from 125 children (mean age 9.5 +/- 3.9; range 0.5-18 years) with newly diagnosed insulin-dependent diabetes mellitus were examined for the presence of antireticulin antibodies (ARA). Fifty-four of these children were followed up over a period of 150-400 days after the onset of the disease with respect to their serum ARA. The indirect immunofluorescence method on human and rat tissue was used to detect autoantibodies. In each serum, the level of islet cell antibodies (ICA) was determined. The prevalence of ARA in our diabetic children (16%) was significantly higher than in normal population (P less than 0.05). In sera of newly diagnosed ICA-negative children, ARA were more frequent than in ICA-positive patients (P less than 0.025). The difference in ARA prevalence was even higher when patients were divided into two groups one with less and one with more than 30 JDFu (P less than 0.005). On the contrary, sera sampled 150-400 days after the manifestation of IDDM revealed neither a positive nor a negative association between ICA and ARA. Thus, the negative association of ARA with ICA in the early stages of IDDM may suggest the role of an autoimmune response to reticulin in part of the IDDM patients, and gives further evidence to the heterogeneity of IDDM.

Transient IgG subclass deficiencies in newly diagnosed diabetic children

In 27 children (15 males and 12 females) with insulin-dependent diabetes mellitus (IDDM), aged 1.2-13.5 years (mean 9.9 +/- 3.6 years) we investigated immunoglobulins (IgG, IgA, IgM), IgG subclass levels and islet-cell antibodies (ICA) at diagnosis and at 6 and 12 months after disease onset. At diagnosis, IgG levels were lower than -2SD in 7 patients (26%), IgA in 1 (3.7%), IgM in 1 (3.7%). IgG subclass levels were below the 3rd percentile in 13 patients (48.1%); in particular IgG1 in 7 (26%), IgG2 in 3 (11.1%), IgG3 in 2 and IgG4 undetectable in 1 case. In 3 out of the 13 patients combined IgG1-IgG3, IgG1-IgG2 and IgG1-IgG4-IgA deficiencies were observed. ICA were greater than 20 Juvenile Diabetes Foundation units in 17/27 patients. The HLA-DR2 frequency was higher in patients with IgG subclass deficiency than in patients with normal IgG subclass levels. During follow up, IgG levels normalized in 6 patients while IgA and IgM did not change. IgG1 normalized in 5 out of the 7 patients, IgG2 in all patients while IgG3 and IgG4 did not change. One year later ICA were still present in 8/27 patients. The hypogammaglobulinaemia and IgG subclass deficiencies observed in our patients could have either a genetic or an acquired basis.

Autoimmunity in vitiligo: relationship with HLA, Gm and Km polymorphisms

Eighty-six patients affected by vitiligo were investigated for Gm, and Km polymorphisms, HLA markers and the presence of organ and non organ-specific autoantibodies. Vitiligo patients had an increased frequency of autoantibodies (71%), in particular anti-parietal cells (26.6%), antithyroglobulin (24.4%) and antithyroid microsomal antibodies (43%). One patient was also affected by Hashimoto's thyroiditis, 4 by Graves' disease and two others by nontoxic, multinodular goiter. No correlation was found between chronologic age and sex and the presence of autoantibodies, while an increased frequency of organ-specific autoantibodies was found with longer duration of vitiligo. HLA-A3 and Gm (3; 23; 5, 10, 11, 13, 14) phenotype frequencies were significantly increased in patients without autoantibodies (P less than 0.05). Patients negative for these two phenotypes were significantly more prone to develop autoantibodies than those positive (P = 0.0032). C4AQO allele showed a significantly decreased frequency in the whole group of patients when compared to the controls (P less than 0.05).

Alterations of in vitro interleukin 1 and 2 in diabetic children

We studied interleukin 1 (IL-1) and interleukin 2 (IL-2) production in unstimulated and stimulated cultures from 27 young diabetic patients and 21 age-matched healthy subjects. In unstimulated cultures monocytes from newly diagnosed patients produced significantly higher levels of IL-1 than controls. In lipopolysaccharide (LPS)-stimulated cultures, IL-1 production in patients with fresh and long-standing diabetes was no different from that of controls. IL-2 production was low or absent in unstimulated cultures from insulin-dependent diabetes mellitus (IDDM) patients and controls. In phytohaemagglutinin (PHA)-stimulated cultures both patient groups produced significantly less IL-2 than controls. No correlation was observed between IL-1, IL-2 production and HbA1 levels or the presence of HLA-DR3 or DR4. Our data on "spontaneous" IL-1 production support the hypothesis that monocytes from some newly diagnosed IDDM patients may circulate in a "preactivated" state. The low levels of IL-2 might be explained by an abnormal consumption or by the presence of increased soluble IL-2 receptor levels or by a serum factor which interferes with IL-2 production. Alternatively, it may be a genetically determined trait.

Autoimmunity, HLA, Gm and Km polymorphisms in Turner's syndrome

Considering the high frequency of autoimmune disorders in Turner's syndrome and the close relationship between autoimmunity, HLA and immunoglobulin constant region gene polymorphisms, we studied 46 patients with Turner's syndrome, by determination of autoantibodies, HLA histoglobulins and Gm and Km allotypes. OSA and in particular PCA resulted significantly more frequent in patients than in the controls. A higher frequency of HLA-A31, B38 antigens and of blanks at HLA-A locus was found in Turner's subjects than in the controls. A31 was significantly more frequent in autoantibody positive patients while B38 was more frequent in autoantibody negative Turner's subjects than in the controls. DR4 antigen was present only in autoantibody negative patients. Gm 3; 23; 5* phenotype was significantly less frequent, while Gm 3;..; 5* phenotype was more frequent in patients than in controls. Our data confirm the higher incidence of autoimmunity disorders in Turner's syndrome than in normal subjects. Particular HLA and immunoglobulin types seem to mark this condition. The increase in the blank frequency at A locus could be explained by the presence of a rare antigen at HLA-A locus or a particularly elevated homozygous condition in these subjects.